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Astrobiology Science Conference 2010 - Part III
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Life and Consequences. I. Mars


One of the most difficult Mars missions ever, will be the Sample Return Mission., returning to earth collected samples from several places on the martian surface , in order to analyze them in detail. (see NASA audio conference). Results of the extreme - environment biology - research will flow into the selective procedures, which specify and choose promising landing areas. Further topics are biologic entities hidden in ecological Mars niches and papers about Mars climate and climate changes in the past.

What happened to Mars?






Thursday, April 29, 2010

WHERE SHOULD WE GO ON MARS TO SEEK SIGNS OF LIFE?

2:00 p.m. Crystal Salon A

This session will focus on the geology and mineralogy most likely to preserve signs of martian life (if any), the evidence for such geology and mineralogy on Mars, and possible targets for future landed missions.



2:45 p.m. Noffke N. *

The Search for Life in the Aquatic Sandy Deposits of Mars: The Criteria for Biogeneicity of Microbially Induced Sedimentary Structures [#5039]

This contribution is a recommendation to the Mars Rover research teams, how to search for modern and ancient microbenthos in the on Mars so common clastic sediments and se-dimentary rocks.

3:00 p.m. Allen C. C. * Oehler D. Z.

Mud Volcanoes as Exploration Targets on Mars [#5172]

Mud volcanoes transport sediments from depth, which could contain chemical biomarkers, mineral biosignatures, or structural remains from past life. We propose that the mud volcanoes in Acidalia may offer a new class of exploration target for Mars.

3:15 p.m. BREAK

3:30 p.m. Levy J. S. * Head J. W. Marchant D. R.

Martian Debris-cvovered Glaciers: Seeking „Signs of Life“ in a ~100 My Old Deep-Freeze [#5059]

Martian debris-covered glaciers should be considered as landing sites in the search for biosignatures, as they represent large volumes of non-polar ice, with a wide regional distribution, unique bio-preservation potential, and intermediate age.




Monday, April 26, 2010

POSTER SESSION: HOW AND WHERE SHOULD WE SEEK SIGNS OF LIFE ON MARS?

6:00 p.m. Marina Plaza Ballroom


Brown I. I. Allen C. C. Tringe S. G. Klatt C. G. Bryant D. A. Sarkisova S. A. Garrison D. H. Mckay D. S.

Microbial Diversity in Surface Iron-rich Aqueous Environments: Implications for Seeking Signs of Life on Mars [#5468]

Comparative analysis of the diversity of organisms in near neutral and acidified Fe-rich water bodies suggests that near neutral iron depositing hot springs have greater potential to preserve extinct or extant life on Mars.

Bonaccorsi R. McKay C. P.


Fairén A. G. Gago-Duport L. Davila A. F. Gil C. McKay C. P.

Subsurface Diffusion of Salt-forming Cations on Early Mars [#5502]

Primeval salt-forming cations were buried under the surface of Mars by diffusion mechanisms, therefore inhibiting the precipitation of sedimentary salts together with phyllosilicates.

Fries M. D. Bhartia R. Beegle L. W. Gursel Y. Mungas G. S.



Allen M. Mischna M. A. Richardson M. I. Newman C. E. Toigo A. D.

The Surface Source of an Atmospheric Trace Gas Plume [#5334]

Trace gases in the atmosphere of Mars can be signatures of subsurface activity, either geological or biological in character. A habitable zone or even an oasis of life may be located below the surface source of such a trace gas.



Wednesday, April 28, 2010

A WARM, WET MARS?

2:00 p.m. Crystal Salon A

Moderator: Alex Pavlov

Dialogers: Brian Toon

Jim Kasting

The discussion will focus on the nature of early Mars' climate and habitability — whether liquid features on the ancient surface of Mars required warm wet climate or intense episodic heating (impacts, giant volcanic eruptions). Is it possible to pull martian climate to warm temperatures with a combination of different greenhouse gases? Or are impacts as a short-term warming mechanism. The debate will stress the limitations and uncertainties of the climate models.

3:30 p.m. BREAK



Thursday, April 29, 2010

HABITABILITY POTENTIAL OF MARS

8:00 a.m. Crystal Salon A

This session explores the habitability of Mars, past and present.

The session will shed light on the possible presence of life on the Red Planet based on latest mission results, relevant analog studies, and promising localities on Mars.

Chairs: Dirk Schulze-Makuch

Alfonso Davila

8:00 a.m. Gibson E. K. * McKay D. S. Thomas-Keprta K. L. Clemett S. J.

Early Mars: A Warm Wet Niche for Life [#5062]

The first 600 My of martian history were ripe for life to develop. Standing bodies of water, precipitation and flowing surface and subsurface water and possibly abundant hydrothermal energy would favor the formation of early life.




8:15 a.m. Fernández-Remolar D. C. * Sánchez-Román M. Hill A. Amils R. Prieto-Ballesteros O. Gómez-Ortíz D. Fernández-Sampedro F. Martín-Redondo M. P.

Global Formation of Carbonates as Indicators of Habitability Emergence on Early Earth and its Implications for Mars [#5324]

Carbonate occurrence on Earth is used to characterize the possible potential habitats and its associated microbial life on early Mars.


8:45 a.m. Devila A. F. * Duport L. G. Melchiorri R. Jänchen J. Valea S. de los Rios A. Fairén A. G. Möhlmann D. McKay C. P. Ascaso C. Wierzchos J.

Hygroscopic Salts: A Habitat for Microorganisms on Mars [#5049]

Hygroscopic salts provide habitable conditions in the driest deserts on Earth. Similar deposits have been identified on Mars and could represent present day habitats.

9:00 a.m. Houtkooper J. M. * Schulze-Makuch D.

Xerophiles on Mars: Possible Evolutionary Strategies Using Hydrogen Peroxide and Perchlorates [#5382]

The Phoenix Lander found surprising amounts of perchlorate salts in the Martian arctic soil. The low water activity and low freezing temperature of a saturated solution of these salts are compatible with putative H2O2-H2O based xerophiles.

9:15 a.m. Renno N. O. * Zorzano M.-P.

Do Brines make the Viking 2 Landing Site Habitable? [#5092]

Renno et al. showed direct evidence that brines are present on Mars’ Arctic. Here we show that brines are also present on mid-latitudes and that this implies that the Viking 2 landing site might have liquid water, one of the key ingredients for life.


9:45 a.m. Archer P. D. Jr * Imanaka H. Smith M. A. Boynton W. V. Smith P. H.

Pyrolysis of UV-Irradiated Organic Molecules — Investigating Potential Martian Organics [#5600]

We show that certain types of organic molecules that might exist on Mars are resistant to UV photolysis. Data obtained by thermal decomposition of irradiated organic molecules could help constrain the chemical composition of Martian organics.


10:30 a.m. Stoker C. R. *

The Habitability of the Phoenix Landing Site: An Evaluation of Mission Results [#5553]

A key objective of the Phoenix mission was to search for a habitable zone. Mission results are used to evaluate the Phoenix site habitability that compares favorably to other sites on Mars. Results show a follow on mission to search for evidence of life is warranted.

10:45 a.m. Chevrier V. F. *

Phyllosilicates, Carbonates, Methane and the Habitability of Nili Fossae on Early Mars [#5180]

Mineral transformations with temperature and CO2 fugacity show that serpentinization affected the primitive crust in the Nili Fossae region, and was accompanied by carbonation and early methane release, making this active environment ideal for life.

11:00 a.m. Wang A. * Freeman J. J. Bell J. F. III Jolliff B. L.

Potential Habitable Zone Within the Subsurface of Equatorial Regions on Mars [#5400]

Spectral changes of salty soils at Gusev suggested a RH gradient within the subsurface, while lab experiments reveal wide stability fields for highly hydrated sulfates at low T-PH2O. A potentially habitable zone may exist in the subsurface on Mars.

11:15 a.m. Jones E. G. Lineweaver C. H. *

The Habitability Potential of Mars [#5178]

We are developing a pressure-temperature model for Mars to identify where the environments are on Mars that may have liquid water and be able to support terrestrial life.

11:30 a.m. Ivarsson M. * Lindgren P.

The Search for Sustainable Subsurface Habitats on Mars[#5123]

Subsurface environments have been targeted as plausible settings for the search for a present or a fossil record of life on Mars, since the current conditions on the martian surface are extremely hostile to life.

11:45 a.m. Boston P. J. * Spilde M. N. Northup D. E. Curry M. D. Melim L. A. Rosales-Lagarde L.

Seekers of Life Below the Surface of Mars[#5346]

Biologically influenced speleothems (biothems) and microbial breakdown products (speleosols) display a set of important unifying properties with predictive power for the subsurface systems of unknown worlds.


12:15 p.m. Des Marais D. J. * Allwood A. C. MEPAG MRR-SAG Team

The Proposed 2018 MAX-C Rover: Exploring for Signs of Life and Caching Samples for Potential Return [#5532]

The Mars Astrobiology Explorer-Cacher (MAX-C) is envisioned as a potential mission to the surface of Mars in 2018 to explore a formerly habitable environment and to collect samples for potential return to Earth by a subsequent mission.

12:30 p.m. LUNCH



Brines = sal****er


DO BRINES MAKE THE VIKING 2 LANDING SITE HABITABLE?Nilton O. Renno1 and Maria Paz Zorzano2,

1University of Michigan, Ann Arbor, USA, 2Centro de Astrobiología (CSIC-INTA), Carretera de Ajalvir Km

4, 28850 Torrejón de Ardoz, Madrid, Spain, renno@alum.mit.edu, zorzanomm@inta.es

Introduction: Salts with extremely low

eutectic temperatures appear to be distributed globally

on Mars [1-6]. Renno et al. [2, 3] showed direct evidence

that these salts absorb water vapor from the

Martian atmosphere and deliquesce. In addition, they

showed observational and theoretical evidence that

freeze-thaw cycles concentrate these salts into eutectic

mixtures and lead to the formation of brine layers a

few centimeters below the surface (Fig. 1).

Zorzano et al. [4] showed that even sodium

perchlorate, a salt with moderately low eutectic

temperature, absorbs water from the air or frost and

forms stable liquid aqueous solutions under the

environmental conditions of the Martian Arctic. …... Here we argue that this

implies that the Viking 2 landing site might have liquid

water, one of the key ingredients for life.

....

Since a thin layer of soil forms a barrier

against sublimation and there is evidence that brines

melt even on Mars’ polar region [2-4], brines can melt

in mid-latitudes and form stable liquid solutions in

regions with atmospheric water column values of ~10

pr-μm, that is approximately ½ the value required for

clear-ice to be stable [8]. …...Conclusions: The discovery of brines on

Mars’ polar region and the evidence for brines in midlatitudes

are significant because they suggest that deliquescence

and therefore liquid saline water is ubiquitous

on Mars......... Indeed, these findings

suggest that liquid saline water could be present a

few centimeters below the surface on the Viking 2

landing site. Therefore this site could have one of the

essential ingredients for life as we know it.








TO SEARCH FOR LIFE ON MARS: FOLLOW THE BRINES. Nilton O. Rennó1, Helga Stan-Lotter2, Eörs

Szathmáry3, D.T.F. Möhlmann4, 1University of Michigan, Ann Arbor, USA; 2University of Salzburg, Salzburg, Austria;

3Collegium Budapest, Budapest, Hungary; 4DLR Institut für Planetenforschung, Berlin, Germany,

renno@alum.mit.edu, helga.stan-lotter@sbg.ac.at, szathmary@colbud.hu, dirk.moehlmann@dlr.de

......

Brines and microbial life: Sulfate, chloride,

and perchlorate salts are present on Mars and, at least

some of these salts appear to be distributed globally [1-

3]. Water molecules from atmospheric water vapor, ice

and interfacial water can deliquesce these salts and

form brines [3-8]. NASA´s Phoenix lander made the

first direct measurement of deliquescence and the formation

of liquid brines on Mars [4-5]. Ionic interactions

allow brines to remain liquid down to temperatures

around 200 K [3-10]. Since halophilic bacteria

thrive on brines, following the brines may lead to life

or biomarkers on Mars, if any exists there [11, 12].

On Earth, hypersaline conditions do not deter

life; on the contrary, halophilic microorganisms thrive

in environments with salt concentrations approaching

saturation levels. Indeed, extremely halophilic archaea

have been isolated from ancient (195-280 million years

old) subsurface salt sediments [12]. Perchloratereducing

bacteria found in terrestrial aquifers might be

relevant to astrobiology [13] because several terrestrial

microbes, ranging from autotrophs (photosynthetic

cyanobacteria and chemoautotrophic sulfur oxidizers)

through anaerobic chemoorganotrophs, sulfate respires,

to methanogens and acetogens can live in

brines, even extremely cold brines. An unanswered

question is how cold can brines be and still allow welladapted

microorganisms to stay alive or sustain

growth. On Mars, current surface temperatures can be

high enough to allow even terrestrial brine-dwellers to

grow. Possible Martian habitats for halophilics include

dark spots on polar sand dunes [14].









NASA - 50 Years of Astrobiology Science[1]_odt_m708a46a3.png






Fig. 1. Evidence for spheroids of liquid brines on a

strut of the Phoenix lander [4, 5].


Climate change and evolution: Climate and

environmental changes were likely faster and more

global on Mars than on Earth. Thus, if microbial life

arose on Mars when it was warmer and wetter, the

selection pressures on Martian microorganisms were

stronger and more widespread than on terrestrial microorganisms,

including terrestrial extremophiles.

....... Therefore, more spectacular extremophiles

could have developed on early Mars than on Earth

[14].....



WATER AT THE PHOENIX LANDING SITE. P. H. Smith1, 1The Lunar and Planetary Lab, University of Arizona,

Tucson, AZ 85721 (psmith@lpl.arizona.edu).

Introduction: The Phoenix mission operated on

the northern plains of Mars (68.2°N, 234.2°E) for 5

months starting on May 25, 2008. The season spanned

Ls 78° – 148° covering most of the northern summer.

Water ice both under the lander and in trenches dug by

the robotic arm was quickly discovered about 5 cm

beneath a dry surface layer. …... identified Ca-carbonate

that buffers the soil chemistry [2], and discovered

perchlorate as an important oxidant [3].

...Significant

water exchange between the regolith and atmosphere

occurs each night with most of the daytime

1.8 Pa of water disappearing from the base of the atmosphere

and a rapid increase toward saturation as

temperatures drop [4].

Frost was observed to deposit

on the surface early in the morning, see Fig. 1.


....

A variety of salts are seen in the wet chemistry experiment

[3]. Finally, lenses of nearly pure ice were

seen that are hard to explain from diffusive vapor

deposition of the ice.

The combination of salts, periodic liquid water, and

chemical energy sources are the ingredients of a habitable

zone [7]. The perchlorate found at about 1% is

used by Earth microbes as an electron acceptor and is

likely to be commonly found in the northern plains.

Future missions should drill deeper into this ice sheet

to find actual evidence of life preserved in the ice.

References: [1] Whiteway, J. (2009) Science, 325, 67.

[2] Boynton, W. V. et al. (2009) Science, 325, 61. [3]

Hecht, M. (2009) Science, 325, 64. [4] Zent. A. P.

(2009) J. Geophys. Res., in press. [5] Levrard, B. et al.

(2007), J. Geophys. Res., 112. [6] Smith, P. H. et al.

(2009) Science, 325, 58. [7] Stoker, C. et al. (2009) J.

Geophys. Res., in press.

 



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